Apple posted the workaround earlier this week. But according to a Microsoft blog post on Thursday, Apple appears to be working on a more complete solution. “Apple has assured us that a fix is being worked on, though they have not commented on a release timeline for the fix,” Adam Glick, senior technical product manager at Microsoft, wrote in a blog post Thursday.

Apple did not reply to a request for further details about a potential fix.

Shortly after the iPhone 4 and its updated operating system hit the market, some users complained about trouble synching with their Exchange accounts. Apple’s workaround can help, because it lengthens the amount of time that the phone tries to connect to an Exchange server, said Lee Dumas, director of architecture for Azaleos, a company that offers managed Exchange services.

While the timeout setting initially was too short, there’s an additional problem that hasn’t yet been fixed, he said. “The new iPhones send requests, and they time out, and they send another, but they aren’t really tearing down the network connection in between the way they should, so what happens is, it exhausts the server,” he said.

Companies that host Exchange servers, either internally or on an outsourced basis, are likely to notice a usage spike because of the networking issue if users of the new iPhone software are connecting to the server, he said.

“Microsoft responded quickly, but the problem is, a lot of engineers may not know what’s happening,” he said.

Dumas suggested that some enterprises may stop allowing the iPhone to retrieve Exchange mail. “I think what might happen is network administrators are just going to block the iPhone, period, and be done with it. That’s what I would do. I’d say you can still read mail but you have to use the Web interface,” he said.

He suggested that the iOS 4 ActiveSync issue reflects Apple’s priorities. “They don’t have a vested interest in the load on an Exchange server,” he said. “The iPhone is not meant to be an enterprise device, and this is a side effect of that.”

One person who posted on the Apple support forum agreed that some businesses might begin to question supporting the iPhone. “This malfunction could turn off a lot of users,” said a person going by the name AustinAtma, who sells and supports Exchange server e-mail to corporate customers, on the forum. “Since Exchange accounts were working perfectly before [iOS 4], it would be good to restore this functionality to the hundreds of thousands of users with Exchange — and it isn’t just large corporations.”